The present invention relates generally to socket joints, more particularly to socket joints that permit rotation of brackets and studs, but resist articulation.
Non-articulating joints are applicable to a wide range of applications, including Pitman-idler arms used in steering linkages of automotive vehicles. Such joints typically include a cylindrical housing member adapted to receive a bearing together with a portion of a stud or bracket. The bearing reduces the amount of friction between the housing and the stud while frequently adapting for wear induced looseness between the stud and housing members.
Such joints have several disadvantages. Typically, the stud head or bracket end must be precisely machined to ensure an adequately tight joint. Further, the stud head or bracket end must be forced into the bearing. Even with such tolerances, some bearings may crack during assembly, particularly when very rigid, stiff, inelastic materials are used. To reduce cracking, heavier material is often used together with slots within the bearing itself. Load distribution in such slotted bearings typically results in undesired wear between the various components. Further, the bearings of such joints are adapted for only limited wear, resulting in joint failure as stud head rotating torque decreases and axial end play increases.
The present invention is directed to a non-articulating joint assembly that is easy to assemble and provides an extremely tight joint having no longitudinal or radial play, but still permits necessary rotation about a longitudinal axis. The joint assembly of the present invention also compensates for wear by having tapered split-half bearing members that permit easy assembly of the joint and axial and radial compression pre-loads. The joint assembly is applicable to a wide variety of applications, including Pitman-idler arms of steering linkages for automotive applications.
The joint assembly of the present invention includes a bracket having a generally cylindrical end portion and a second end having a bracket mounting portion. A socket member includes a housing with a bore therethrough. The bore being defined by a tapered inner wall surface, receives the bracket. In addition, a generally hollow, tapered split-half bearing assembly is positioned around the cylindrical end portion of the bracket with the tapered outside surface matingly contacting the tapered inner wall surface of the housing. The angle of taper for both the inner wall surface of the housing and the outer surface of the split-half bearings is preferably in the range of 1xc2x0-3xc2x0. Further, a pre-loaded cap bearing assembly, that includes a cap bearing, a spring member and a closure plate, is received in the housing and contacts a bottom surface of the split-half bearing assembly. Thus, the split-half bearing assembly is axially captured within the housing and the cap bearing assembly. It cooperates with the tapered split-half bearing members and tapered inner surface to pre-load the joint and prevent articulation. The closure member further serves to prevent dirt and debris from entering the joint assembly. A rim on the housing is crimped over to securely hold the joint assembly together. In addition, crimping produces an axial pre-load on the split-half bearing assembly. The split-half bearing assembly and the cap bearing of the present invention can further include a plurality of lubrication channels for re-lubricating the joint.
The axial and radial pre-loading in the present invention provides a greater range of tolerances in manufacturing the components. Increased tolerances result in reduced production costs and reduced scrap rates. The axial and radial compression pre-loads also maintain tightness in the joint assembly by compensating for wear. Further, the split-half bearing assembly permits quick and easy assembly of the joint without cracking problems.
The present invention also provides for a second housing having a second bore with a tapered inner wall surface located at an opposite end of the socket member. The second housing receives a stud having a threaded fastening portion at one end and a generally cylindrical end portion at an opposite end. The cylindrical end portion of the stud is received within a second split-half bearing assembly having a similar design to the first cap bearing, mentioned above. A second cap bearing assembly is also positioned to be adjacent split-half bearing assembly and the closure plate of the cap bearing assembly is captured by a portion of second housing that is crimped over to provide an axial and radial pre-load on the joint assembly.
Accordingly, the present invention provides a joint assembly having no longitudinal or radial end play and reduced production costs due to the use of increased manufacturing tolerances. Moreover, the joint assembly of the present invention has an increased service life by reducing unwanted end play.